Acer is a bit more expensive but i get 8gb ram and 1tb storage which is double.
i use the internet alot esp. Opening multiple tabs and windows (videos and stuff).
i've heard lenovo is a good brand but i think acer appeals more to me but i never really had any so i don't know what i should go for.
Added (1). i think some places show acer with 4gb ram but i'm looking for the 8gb ram (below)
The Acer gets 4.5 Stars out of Five at Amazon. Must be all right. This model is 500GB HD, but the rest is similar.
http://www.amazon.com/...B00M8RO9WS
You can get different specs of the Lenovo G50-70 and the Acer E5-571. Do you know which one in specific you would like? For example you can get i3, i5 or an i7 4th generation processor. For the sake of comparing them I will use the Intel core i3 processor.
Also on the Acer website it says that the HDD is 500GB rather than 1TB. That being said, you can upgrade your HDD to a 1TB hard drive.
The processors are the same one, both are the Intel core i3-4030U which would be fitting for you based on what you stated the use of the laptop would be so processor wise, they are the same.
Both have 8GB of DDR3L RAM which is also a good fit for your intended use, both are 15.6" with the same resolution. Upon reading the specs, they have the exact same specs. It's mostly just personal preference from here.
My personal opinion would be the Acer but that is because I work with computers on a daily basis and I have used both Acer as well as Lenovo. Personally. I strongly dislike the laptops that Lenovo makes, they really don't look nice and are pretty horridly designed. Acer usually sticks to the black on black theme of laptops with sort of a gritty feel. I dislike the Acer trackpads because of the clicking.
So it seems as though either or would be a good choice for you based on the intended use. You should watch reviews on both models and study them or even go into your local electronic store and look for them on display. Best of luck, hope I was somewhat helpful.